JP2012129060A - Flat sofc stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately supply fuel and air to a central region of unit cells while reducing the thickness of separator.SOLUTION: A common separator 10 disposed between adjacent power generation units comprises: a fuel center supply path 11 for supplying fuel to one power generation unit; and an air center supply path 12 for supplying air to the other power generation unit. The fuel center supply path 11 is extended toward a central region in a groove in a surface 10A placed in contact with a fuel passage plate 4, and the air center supply path 12 is extended toward the central region in a groove in a surface 10B placed in contact with an air passage plate 5 so as not to pass over/under the fuel center supply path 11. The fuel passage plate 4 has a fuel supply hole 4A connecting a tip opening 11A to a central region of a fuel passage 4B, and the air passage plate 5 has an air supply hole 5A connecting a tip opening 12A to a central region of an air passage 5B.

Description

  The present invention relates to a flat plate solid oxide fuel cell stack in which a plurality of single cells including flat plate solid oxide fuel cells are stacked.

  A flat plate fuel cell forms a single cell with an electrolyte composed of a flat plate and an air electrode and a fuel electrode formed on the front and back surfaces of the electrolyte, and supplies and exhausts fuel gas and oxidant gas to the fuel electrode and air electrode, respectively. A fuel cell stack is formed by stacking a plurality of power generation units interposing a single cell in a state of sandwiching a single cell with a separator having a passage to form a fuel cell stack. In this fuel cell, power is generated by supplying fuel gas and oxidant gas to each electrode of a single cell.

FIG. 14 is a plan view of a power generation unit used in a conventional flat solid oxide fuel cell (Solid Oxide Fuel Cell: hereinafter referred to as flat SOFC) stack, and FIG. 15 is a power generation unit used in a conventional flat SOFC stack. FIG. 16 is a cross-sectional view of a conventional flat plate type SOFC stack (cross-sectional view).
The power generation unit 301 of the flat plate type SOFC stack 300 includes a single cell 1, a cell holder 2, an insulating member 3, a fuel flow path plate 4, an air flow path plate 5, a fuel center supply plate 31, and an air center supply plate 32. Yes.

  The single cell 1 is a fuel electrode support type cell having a disk shape (disc shape) as a whole, an electrolyte 1C made of a flat plate, a fuel electrode 1A made of a flat plate formed on one surface of the electrolyte 1C, and It is comprised from the air electrode 1B which consists of a flat plate formed in the other surface of 1 C of electrolytes.

  The single cell 1 is supported by a support hole 2 </ b> A of the cell holder 2 and is disposed at a predetermined position between the fuel flow path plate 4 and the air flow path plate 5. The fuel electrode 1A of the single cell 1 is pressed and held by the fuel flow path plate 4 toward the electrolyte 1C, and the air electrode 1B of the single cell 1 is pressed and held by the air flow path plate 5 toward the electrolyte 1C. Has been. An insulating member 3 is provided between the cell holder 2 and the air flow path plate 5 to electrically insulate both from each other and to seal the mixture of air and fuel.

The cell holder 2, the insulating member 3, the fuel flow path plate 4, the air flow path plate 5, the fuel center supply plate 31, and the air center supply plate 32 have a generally rectangular shape in plan view as a whole, and are disposed at the center thereof. A plurality of through-holes having a substantially circular cross section are formed around the single cell 1 along the stacking direction. These through holes are used as a fuel supply manifold 21, an air supply manifold 22, a fuel exhaust manifold 23, and an air exhaust manifold 24.
Each separator of the fuel flow path plate 4, the air flow path plate 5, the fuel center supply plate 31, and the air center supply plate 32 is a metal plate provided with various patterns by, for example, etching, cutting, or pressing. It is configured.

  The fuel center supply plate 31 is provided on the surface of the fuel flow path plate 4 opposite to the single cell 1, and the fuel flow path plate 4 side surface of the fuel center supply plate 31 is connected to the fuel supply manifold 21. A fuel center supply path 31 </ b> A for supplying fuel toward the center of the single cell 1 is provided. Thus, the fuel is supplied from the fuel supply manifold 21 to the center of the single cell 1 through the fuel center supply path 31A, and then passes through the fuel supply hole 4A provided in the center of the fuel flow path plate 4. And supplied to the center of the fuel electrode 1A.

  A fuel flow path 4B is provided on the surface of the fuel flow path plate 4 on the single cell 1 side to distribute the fuel onto the surface of the fuel electrode 1A and simultaneously take out electricity from the fuel electrode 1A. As a result, the fuel supplied from the fuel supply hole 4A is used for power generation while flowing in the fuel flow path 4B from the center to the periphery of the fuel electrode 1A, and passes through the fuel discharge path 4C to the fuel exhaust manifold. 23 is discharged. The fuel exhaust may have an exhaust structure other than the above.

  The air center supply plate 32 is provided on the surface of the air flow path plate 5 opposite to the single cell 1, and the air flow path plate 5 side of the air center supply plate 32 is connected to the air supply manifold 22. An air center supply path 32 </ b> A that supplies air toward the center of the single cell 1 is provided. As a result, air is supplied from the air supply manifold 22 to the center of the single cell 1 through the air center supply path 32A, and then passes through the air supply hole 5A provided in the center of the air flow path plate 5. And supplied to the center of the air electrode 1B.

  In addition, an air flow path 5B is provided on the surface of the air flow path plate 5 on the unit cell 1 side to distribute air on the surface of the air electrode 1B and simultaneously take out electricity from the air electrode 1B. As a result, the air supplied from the air supply hole 5A is used for power generation while flowing in the air flow path 5B from the center portion to the peripheral portion of the air electrode 1B, and passes through the air discharge path 5C to be an air exhaust manifold. It is discharged to 24. Note that the air exhaust may have an exhaust structure other than the above.

Masayuki Yokoo, Yoshitaka Tabata, Yoshiaki Yoshida, Himeko Hime, Katsuya Hayashi, Kazuhiko Nozawa, Yosuke Nozaki, Hajime Arai, "Development of Internal Manifold Type SOFC Stacks at NTT", 16th SOFC Research Meeting Presentation, pp. 2 -5, 2003

  As shown in FIG. 15, when the flat SOFC single cell 1 has a disk shape as a whole, the fuel and air are simply separated from the viewpoint of the distribution of the fuel and air in the cell plane and the sealing of the fuel and air. It is desirable to distribute to the peripheral part of the single cell 1 after supplying it to the central part of the cell 1. Further, from the viewpoint of saving space and reducing pressure loss, it is desirable that the depth of the groove provided in the separator be as small as possible, specifically at least half the thickness of the separator.

In consideration of such points, in the above-described conventional technology, as shown in FIG. 15, in order to supply fuel and air to the central portion of the single cell 1, the fuel center supply path 31A and the air center supply path 32A are provided. As the separator to be formed, one fuel center supply plate 31 and one air center supply plate 32 are used.
However, in this structure, the height (thickness) of the power generation unit 201 in the stacking direction increases according to the thickness of the fuel center supply plate 31 and the air center supply plate 32, so the entire flat SOFC stack is made compact. There was a problem that it was difficult to do.

  The present invention is for solving such problems, and an object of the present invention is to provide a flat-plate SOFC stack that can appropriately supply fuel and air to the center of a single cell while reducing the thickness of the separator. Yes.

  In order to achieve such an object, a flat plate SOFC stack according to the present invention includes a flat plate solid oxide fuel cell (hereinafter referred to as flat plate SOFC) composed of a fuel electrode, an air electrode, and an electrolyte of a solid oxide. A flat plate type SOFC stack formed by stacking and electrically connecting power generation units each having a single cell and a separator provided with a path for supplying fuel and air to the single cell. The separator includes a fuel flow path plate provided with a fuel flow path for supplying fuel to the fuel electrode, and an air flow path plate provided with an air flow path for supplying air to the air electrode. Separately from the separators of two adjacent power generation units by stacking, a fuel center supply path for supplying fuel from the fuel supply manifold to one power generation unit, and an empty And a common separator having an air center supply path for supplying air to the other power generation unit from the supply manifold.

  The fuel center supply path extends in a groove shape from the fuel supply manifold toward the center of the common separator on the first surface of the common separator that contacts the fuel flow path plate of one of the power generation units. The supply path has a groove shape on the second surface of the common separator that is in contact with the air flow path plate of the other power generation unit and opposite to the first surface so as not to three-dimensionally intersect the fuel center supply path. And the fuel flow path plate is provided at a position facing the substantially central part of the fuel electrode, and the front end opening of the fuel center supply path and the fuel flow path The air flow path plate is provided at a position facing the substantially central portion of the air electrode, and the front end opening of the air center supply path and the central portion of the air flow path are connected to the central portion of the air flow path. Has an air supply hole to connect

  At this time, the fuel supply hole is formed by a circular hole having a radius including the center of the fuel electrode to the tip opening of the fuel center supply path, and the air supply hole is formed from the center of the air electrode to the center of the air center supply path. You may form with the circular hole which has a radius including a tip opening part.

  Further, the fuel supply hole is formed by an elliptical or oval hole having a long diameter including the center of the fuel electrode and the tip opening of the fuel center supply path, and the air supply hole is formed from the center of the air electrode to the air center. You may form by the ellipse-shaped or ellipse-shaped hole which has a long diameter including the tip opening part of a supply path | route.

  Further, either one or both of the fuel center supply path and the air center supply path may be formed in a slit shape that penetrates the first surface and the second surface of the common separator.

  According to the present invention, it is possible to halve the number of separators for constructing a fuel and air supply path without increasing the thickness of the separator, and as a result, it is possible to make the flat plate SOFC stack compact. It becomes. Further, even when fuel and air supply paths are separately formed on both surfaces of one common separator, the fuel and air are fed to the center of the fuel flow path and the air flow path without crossing these supply paths in three dimensions. Can be supplied. Therefore, even when the flat SOFC stack is made compact, fuel and air can be appropriately supplied to the center of the single cell, and high power generation efficiency can be obtained.

It is a block diagram which shows the structure of the flat type SOFC stack concerning 1st Embodiment. It is II-II sectional drawing of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a lamination example (sectional view) of the flat plate type SOFC stack concerning a 1st embodiment. It is a top view of a cell holder. It is a top view of an insulating member. It is explanatory drawing of a fuel flow-path board. It is explanatory drawing of an air flow path board. It is explanatory drawing of a common separator. It is a block diagram which shows the structure of the flat type SOFC stack concerning 2nd Embodiment. It is XI-XI sectional drawing of FIG. It is explanatory drawing of the fuel flow-path board used by 2nd Embodiment. It is explanatory drawing of the air flow path board used by 2nd Embodiment. It is a top view of the electric power generation unit used with the conventional flat type SOFC stack. It is AA sectional drawing of the electric power generation unit used with the conventional flat type SOFC stack. It is a lamination example (cross-sectional view) of a conventional flat plate type SOFC stack.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a flat SOFC stack according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a flat plate-type SOFC stack according to the first embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a stacking example (cross-sectional view) of the flat plate type SOFC stack according to the first embodiment. 1 to 4, the same or equivalent parts as those in FIGS. 14 to 16 are denoted by the same reference numerals.

  The flat plate type SOFC stack 100 includes a flat plate type SOFC single cell composed of a fuel electrode, an air electrode, and a solid oxide electrolyte, and a separator provided with a path for supplying fuel and air to the single cell. It is formed by stacking the power generation units provided and electrically connecting them in series.

[Principle of the Invention]
In general, in the SOFC, a generated voltage per unit cell, so-called cell voltage, is around 0.7 V, and it is necessary to stack many single cells to obtain a practical voltage. For this reason, in order to make the flat SOFC stack compact, it is necessary to reduce the thickness of the separator as much as possible.
On the other hand, it is necessary to supply a sufficient amount of fuel and air in order to efficiently generate power in each single cell. Therefore, if the separator is made thinner than necessary, the cross-sectional area of the supply path provided in the separator is reduced, and the amount of fuel and air supplied is reduced, resulting in a reduction in power generation efficiency.

Further, in the flat plate type SOFC stack, the laminated separator is pressed for sealing of fuel and air, and the SOFC itself operates at a high temperature of 700 ° C. to 1000 ° C. For this reason, if the separator is made thinner than necessary, the strength of the separator decreases at a high temperature, and the supply path provided in the separator may be deformed and blocked.
Therefore, it is necessary to design the thickness of the separator to a thickness necessary to form a supply path that can supply a sufficient amount of fuel and air.

  The present invention pays attention to the fact that a fuel and air supply path is conventionally configured using a separate separator for each power generation unit, and a separate common separator independent of the power generation unit is newly provided between each power generation unit. The fuel supply path of one power generation unit of the two adjacent power generation units and the air supply path of the other power generation unit are configured by one common separator.

  In addition, in order to efficiently form a supply path in a separator having a limited thickness, fuel and air supply paths are separately formed on two surfaces of the common separator, that is, the front surface and the back surface. Is formed so as not to cross three-dimensionally in plan view. Thereby, both fuel and air supply paths can be formed with the same thickness as the conventional separator. At this time, in order to efficiently form the supply path in the separator having a limited thickness, the depth of the supply path may be set to be more than half the thickness of the common separator.

  Therefore, the number of separators for configuring the fuel and air supply paths can be halved without increasing the thickness of the separator, and as a result, the flat-plate SOFC stack can be made compact.

  Further, as described above, when the flat SOFC single cell has a disk shape as a whole, the fuel and air are separated from the single cell in terms of the distribution of the fuel and air in the cell plane and the sealing of the fuel and air. It is desirable to distribute to the peripheral part of the single cell after supplying to the central part.

  However, if the fuel and air supply paths are provided from the fuel exhaust manifold or air supply manifold to the center of the fuel flow path or air flow path, the fuel and air supply paths should intersect three-dimensionally at the center. become.

  For this reason, in the present invention, the separator constituting the fuel flow path in the power generation unit, that is, the fuel flow path plate, is common to the central part of the fuel flow path at a position facing the substantially central part of the fuel electrode of the single cell. A fuel supply hole is provided for connecting the front end opening of the fuel supply path of the separator, and the separator constituting the air flow path in the power generation unit, that is, the substantially central part of the air electrode of the single cell in the air flow path plate An air supply hole for connecting the central portion of the air flow path and the front end opening of the air supply path of the common separator is provided at the facing position.

As a result, even when fuel and air supply paths are separately formed on both surfaces of one common separator, the fuel and air flow into the center of the fuel flow path and the air flow path without crossing these supply paths in three dimensions. Can be supplied.
Therefore, even when the flat SOFC stack is made compact, fuel and air can be appropriately supplied to the center of the single cell, and high power generation efficiency can be obtained.

The present embodiment has the following configuration based on the principle of the invention.
That is, the separator includes a fuel flow path plate provided with a fuel flow path for supplying fuel to the fuel electrode, and an air flow path plate provided with an air flow path for supplying air to the air electrode. Separately from the separators of two adjacent power generation units by stacking, a fuel center supply path for supplying fuel from the fuel supply manifold to one power generation unit, and air from the air supply manifold to the other power generation A common separator having an air center supply path for supplying to the unit.

  The fuel center supply path extends from the fuel supply manifold toward the center of the common separator in a groove shape on the first surface of the common separator that is in contact with the fuel flow path plate of one power generation unit. A groove is provided on the second surface of the common separator that is in contact with the air flow path plate of the other power generation unit and that is opposite to the first surface so as not to three-dimensionally intersect the fuel center supply route. It extends in the shape from the air supply manifold toward the central part of the common separator, and is provided on the fuel flow path plate at a position facing the substantially central part of the fuel electrode. A fuel supply hole is provided for connecting the center of the passage, and the air passage plate is provided at a position facing the substantially central portion of the air electrode. Sky to connect parts It is provided with a feed hole.

[Configuration of First Embodiment]
Next, the configuration of the flat plate-type SOFC stack 100 according to the present embodiment will be described in detail with reference to FIGS.
The power generation unit 101 of the flat plate SOFC stack 100 includes a single cell 1, a cell holder 2, an insulating member 3, a fuel flow path plate 4, and an air flow path plate 5. Further, these power generation units 101 (101M) are stacked on each other with the common separator 10 interposed between adjacent power generation units 101 (101N).

The single cell 1 is a fuel electrode support type cell having a disk shape (disc shape) as a whole, an electrolyte 1C made of a flat plate, a fuel electrode 1A made of a flat plate formed on one surface of the electrolyte 1C, and It is comprised from the air electrode 1B which consists of a flat plate formed in the other surface of 1 C of electrolytes.
The single cell 1 is supported by a support hole 2 </ b> A of the cell holder 2 and is disposed at a predetermined position between the fuel flow path plate 4 and the air flow path plate 5. The fuel electrode 1A of the single cell 1 is pressed and held by the fuel flow path plate 4 toward the electrolyte 1C, and the air electrode 1B of the single cell 1 is pressed and held by the air flow path plate 5 toward the electrolyte 1C. Has been.

The cell holder 2, the insulating member 3, the fuel flow path plate 4, the air flow path plate 5, and the common separator 10 have a substantially rectangular shape in plan view as a whole, and the center of each cell is the single cell 1, and further the fuel electrode 1A and The air electrode 1B is disposed in alignment with the central axis.
Among these, the cell holder 2, the fuel flow path plate 4, the air flow path plate 5, and the common separator 10 are made of metal plates in which patterns such as various holes and grooves are formed by etching, cutting, or pressing, for example. ing.

  In addition, a substantially circular cross-section is formed around the cell holder 2, the insulating member 3, the fuel flow path plate 4, the air flow path plate 5, and the single cell 1 located at the center of the common separator 10 along the stacking direction. A plurality of through holes are formed. These through holes are used as paths for supplying and exhausting fuel and air, that is, as a fuel supply manifold 21, an air supply manifold 22, a fuel exhaust manifold 23, and an air exhaust manifold 24.

  FIG. 5 is a plan view of the cell holder. The cell holder 2 is provided with a support hole 2A for supporting the unit cell 1 at the center thereof. The cell holder 2 may be formed integrally with the fuel flow path plate 4 by increasing the height of the peripheral edge of the fuel flow path plate 4.

  FIG. 6 is a plan view of the insulating member. The insulating member 3 is an electrically insulating member having a donut plate shape in plan view, and is electrically connected to a cell holder 2 electrically connected to a fuel electrode 1A forming an anode electrode and an air electrode 1B forming a cathode electrode. It has the function of electrically insulating the air flow path plate 5 connected to the air and the function of sealing the mixture of air and fuel.

  FIG. 7 is an explanatory view of the fuel flow path plate, FIG. 7 (a) is a plan view of the fuel flow path plate, and FIG. 7 (b) is a bottom view of the fuel flow path plate. The fuel flow path plate 4 is formed at a position facing the substantially central portion of the fuel electrode 1A and at a position facing the fuel electrode 1A, and fuel is supplied from the fuel supply hole 4A to the fuel electrode 1A. And a fuel discharge path 4C that connects the fuel flow path 4B and the fuel exhaust manifold 23. The fuel exhaust may have an exhaust structure other than the above.

  The fuel supply hole 4A has a shape that connects the tip opening 11A of the fuel center supply path 11 of the common separator 10 and the center of the fuel flow path 4B. FIG. 7 shows an example in which the fuel supply hole 4A is configured as a circular hole having a radius including the center P of the fuel electrode 1A to the tip opening 11A of the fuel center supply path 11. As a result, the fuel supply hole 4A can be formed by an extremely simple process of providing a circular hole at the center of the fuel flow path plate 4, and the manufacturing cost can be greatly reduced.

  FIG. 8 is an explanatory view of an air flow path plate, FIG. 8 (a) is a plan view of the air flow path plate, and FIG. 8 (b) is a bottom view of the air flow path plate. The air flow path plate 5 is formed at an air supply hole 5A provided at a position facing the substantially central portion of the air electrode 1B and at a position facing the air electrode 1B, and air is supplied from the air supply hole 5A to the air electrode 1B. And an air discharge path 5C for connecting the air flow path 5B and the air exhaust manifold 24 to each other. Note that the air exhaust may have an exhaust structure other than the above.

  In addition, the air supply hole 5A has a shape that connects the tip opening 12A of the air center supply path 12 of the common separator 10 and the center of the air flow path 5B. FIG. 8 shows an example in which the air supply hole 5A is configured as a circular hole having a radius including the center P of the air electrode 1B to the tip opening 12A of the air center supply path 12. Thereby, the air supply hole 5A can be formed by an extremely simple processing process of providing a circular hole at the center of the air flow path plate 5, and the manufacturing cost can be greatly reduced.

FIG. 9 is an explanatory diagram of the common separator, FIG. 9A is a plan view of the common separator, and FIG. 9B is a bottom view of the common separator.
The common separator 10 includes a fuel center supply path 11 that supplies fuel from the fuel supply manifold 21 to the fuel supply hole 4A of one power generation unit 101M, and air from the air supply manifold 22 among the adjacent power generation units 101M and 101N. Is provided to the air supply hole 5A of the other power generation unit 101N.

  The common separator 10 has a surface 10A (first surface) in contact with the fuel flow path plate 4 of one power generation unit 101M on the fuel flow path plate 4 side from the fuel supply manifold 21 toward the center of the common separator 10. A groove-shaped fuel center supply passage 11 is provided extending in the groove. The extended end opening 11A of the fuel center supply path 11 is connected to the fuel supply hole 4A of one power generation unit 101M at the center of the common separator 10.

  Further, the common separator 10 has a central portion of the common separator 10 from the air supply manifold 22 to a surface 10B (second surface) opposite to the surface 10A that contacts the air flow path plate 5 of the other power generation unit 101N. A groove-shaped air center supply path 12 that opens to the air flow path plate 5 side is extended so as not to three-dimensionally intersect the fuel center supply path 11. The extended front end opening 12A of the air center supply path 12 is connected to the air supply hole 5A of the other power generation unit 101N at the center of the common separator 10.

  The fuel center supply path 11 and the air center supply path 12 have a groove shape with a rectangular cross section or a curved shape. Regarding the field and depth (height) of the fuel center supply path 11 and the air center supply path 12, the values of the respective design ranges are selected in consideration of the drop in pressure loss of the fuel and air supplied to the power generation unit 1. do it.

About the depth (height) of the fuel center supply path 11 and the air center supply path 12, for example, by setting the depth (height) to more than half of the thickness of the common separator 10, the common thickness limited by various conditions as described above is used. In the separator, it is possible to form a supply path capable of supplying a larger amount of fuel and air while suppressing pressure loss.
Further, since the fuel center supply path 11 and the air center supply path 12 do not intersect three-dimensionally, the fuel center supply path 11 and the air center supply path 12 may have a slit shape penetrating the surfaces 10A and 10B of the common separator 10.

  The fuel center supply path 11 and the air center supply path 12 are arranged at positions that do not cross three-dimensionally. If a through hole is formed in the fuel center supply path 11 and the air center supply path 12, the fuel and air are burned before being supplied to the single cell 1, and the power generation performance is significantly reduced. Therefore, the fuel center supply path 11 And the air center supply path 12 are arranged so as not to interfere with each other.

The fuel center supply path 11 and the air center supply path 12 approach at the center of the common separator 10. In the example of FIG. 9, both the fuel center supply path 11 and the air center supply path 12 have a structure that does not reach the center of the common separator 10, but only one of them reaches the center if they do not interfere with each other. It does not matter if there is no structure.
Further, a groove-shaped auxiliary path is formed on the surface of the fuel flow path plate 4 and the air flow path plate 5 that contacts the common separator 1 to assist the fuel center supply path 11 and the air center supply path 12. Thus, the pressure loss of fuel or air may be reduced.

[Effect of the first embodiment]
Thus, this embodiment is provided between the separators of the two power generation units 101M and 101N adjacent to each other by stacking separately from the separators such as the fuel passage plate 4 and the air passage plate 5. A common separator 10 having a fuel center supply path 11 for supplying fuel from the manifold 21 to one power generation unit 101M and an air center supply path 12 for supplying air from the air supply manifold 22 to the other power generation unit 101N. It is.

  The fuel center supply path 11 is extended from the fuel supply manifold 21 toward the center of the common separator 10 in a groove shape on the surface 10A of the common separator 10 that contacts the fuel flow path plate 4 of one power generation unit 101M. At the same time, the air center supply path 12 is three-dimensionally intersected with the fuel center supply path 11 on the surface 10B opposite to the surface 10A that contacts the air flow path plate 5 of the other power generation unit 101N in the common separator 10. The fuel center supply path 11 is formed in a groove shape so as to extend from the air supply manifold 22 toward the central portion of the common separator 10 and to the fuel flow path plate 4 at a position facing the substantially central portion of the fuel electrode 1A. A fuel supply hole 4A is provided to connect the tip opening 11A of the fuel cell and the center of the fuel flow path 4B, and the air flow path plate 5 faces the substantially central part of the air electrode 1B. The location, is provided with a air supply hole 5A which connects the center portion of the distal end opening portion 12A and the air channel 5B of the air around the supply path 12.

Accordingly, the number of separators for configuring the fuel and air supply paths can be halved without increasing the thickness of the separator, and as a result, the flat-plate SOFC stack can be made compact.
Further, even when fuel and air supply paths are separately formed on both surfaces of one common separator, the fuel and air are fed to the center of the fuel flow path and the air flow path without crossing these supply paths in three dimensions. Can be supplied. Therefore, even when the flat SOFC stack is made compact, fuel and air can be appropriately supplied to the center of the single cell, and high power generation efficiency can be obtained.

  In the present embodiment, the cell holder 2, the insulating member 3, the fuel flow path plate 4, the air flow path plate 5, and the through holes provided in the peripheral part of the common separator 10 are provided in the fuel supply manifold 21 and the air supply manifold 22. In the above description, the fuel exhaust manifold 23 and the air exhaust manifold 24 are used as examples. However, the fuel and air are not supplied through such a through-hole and are supplied by a manifold provided outside the flat plate SOFC stack 100. You may make it exhaust.

  In this case, in the common separator 10, the fuel center supply path 11 may be extended from the fuel intake provided in the outer peripheral portion of the common separator 10 toward the center of the common separator 10, and the air center supply path 12 is What is necessary is just to extend toward the center part of the common separator 10 from the air intake provided in the outer peripheral part of the common separator 10.

[Second Embodiment]
Next, a flat SOFC stack 100 according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a block diagram illustrating a configuration of a flat plate SOFC stack according to the second embodiment. 11 is a cross-sectional view taken along the line XI-XI in FIG.

In the first embodiment, the case where the fuel supply hole 4A of the fuel flow path plate 4 and the air supply hole 5A of the air flow path plate 5 are configured in a circular shape has been described as an example. In the present embodiment, the case where the fuel supply hole 4A and the air supply hole 5A are configured in an elliptical shape will be described as an example.
In the present embodiment, the configuration other than the fuel supply hole 4A and the air supply hole 5A is the same as that of the first embodiment described above, and a detailed description thereof is omitted here.

  FIG. 12 is an explanatory view of a fuel flow path plate used in the second embodiment. FIG. 12 (a) is a plan view of the fuel flow path plate, and FIG. 12 (b) is a bottom view of the fuel flow path plate. FIG. The fuel supply hole 4 </ b> A provided in the fuel flow path plate 4 has a shape for connecting the tip opening 11 </ b> A of the fuel center supply path 11 of the common separator 10 and the center of the fuel flow path 4 </ b> B. FIG. 12 shows an example in which the fuel supply hole 4A is configured as an elliptical hole having a long diameter including the center P of the fuel electrode 1A to the tip opening 11A of the fuel center supply path 11.

  FIG. 13 is an explanatory view of an air flow path plate used in the second embodiment. FIG. 13 (a) is a plan view of the air flow path plate, and FIG. 13 (b) is a bottom surface of the air flow path plate. FIG. The air supply hole 5 </ b> A provided in the air flow path plate 5 has a shape that connects the tip opening 12 </ b> A of the air center supply path 12 of the common separator 10 and the center of the air flow path 5 </ b> B. FIG. 13 shows an example in which the air supply hole 5A is configured as a circular hole having a long diameter including the center P of the air electrode 1B to the tip opening 12A of the air center supply path 12.

  The fuel flow path 4B of the fuel flow path plate 4 has not only a function of supplying fuel to the fuel electrode 1A of the single cell 1, but also a function of collecting electromotive force generated in the single cell 1. For this reason, it is necessary to efficiently collect the electromotive force in the fuel flow path plate 4 via a current collector such as a foam metal that forms the fuel flow path 4B. Therefore, the current collection efficiency is higher as the electrical contact area between the current collector and the fuel flow path plate 4 is larger.

  The air flow path 5B of the air flow path plate 5 has not only a function of supplying fuel to the air electrode 1B of the single cell 1, but also a function of collecting electromotive force generated in the single cell 1. For this reason, it is necessary to efficiently collect the electromotive force by the air flow path plate 5 via a current collector such as a foam metal that forms the air flow path 5B. Therefore, the current collection efficiency is higher as the electrical contact area between the current collector and the air flow path plate 5 is larger.

  In the present embodiment, since the area of the fuel supply hole 4A and the air supply hole 5A can be reduced as compared with the first embodiment, the current collector and the fuel flow path plate 4 or the air flow path plate The electrical contact area with 5 can be increased, and the current collection efficiency can be increased. Moreover, since the location where fuel and air are supplied to the fuel flow path 4B and the air flow path 5B can be concentrated in the central portion and the ratio of supply from other than the central portion can be reduced, the fuel electrode 1A and the air electrode 1B On the other hand, more fuel and air can flow from the center to the peripheral direction, and the power generation efficiency can be improved.

[Effect of the second embodiment]
Thus, in the present embodiment, the fuel supply hole 4A of the fuel flow path plate 4 is configured by an elliptical hole having a long diameter including the center of the fuel electrode 1A to the tip opening 11A of the fuel center supply path 11. Since the air supply hole 5A of the air flow path plate 5 is configured by an elliptical hole having a long diameter including the center of the air electrode 1B to the tip opening 12A of the air center supply path 12, the current collector and the fuel The electrical contact area with the flow path plate 4 and the air flow path plate 5 can be increased, and the current collection efficiency can be increased.
In addition, the fuel supply hole 4A and the air supply hole 5A can be formed by an extremely simple processing process of providing an elliptical hole in the fuel flow path plate 4 and the air flow path plate 5, which greatly increases the manufacturing cost. Can be reduced.

[Third Embodiment]
Next, a flat SOFC stack 100 according to a third embodiment of the present invention will be described.
In the second embodiment, the case where the fuel supply hole 4A of the fuel flow path plate 4 and the air supply hole 5A of the air flow path plate 5 are configured in an elliptical shape has been described as an example. It may be a shape.

That is, in the present embodiment, the fuel supply hole 4A of the fuel flow path plate 4 is composed of an oblong hole having a long diameter including the center P of the fuel electrode 1A to the tip opening 11A of the fuel center supply path 11. Has been.
The air supply hole 5 </ b> A of the air flow path plate 5 is composed of an oblong hole having a long diameter including the center P of the air electrode 1 </ b> B to the tip opening 12 </ b> A of the air center supply path 12.

[Effect of the third embodiment]
Thereby, similarly to the second embodiment, the electrical contact area between the current collector and the fuel flow path plate 4 or the air flow path plate 5 can be increased, and the current collection efficiency can be increased. .
In addition, the fuel supply hole 4A and the air supply hole 5A can be formed by an extremely simple processing process of providing an oblong hole in the fuel flow path plate 4 and the air flow path plate 5, which greatly increases the manufacturing cost. Can be reduced.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... Flat type SOFC stack, 101, 101M, 101N ... Power generation unit, 1A ... Fuel electrode, 1B ... Air electrode, 1C ... Electrolyte, 2 ... Cell holder, 3 ... Insulating member, 4 ... Fuel flow path plate, 4A ... Fuel supply Hole, 4B ... Fuel flow path, 4C ... Fuel discharge path, 5 ... Air flow path plate, 5A ... Air supply hole, 5B ... Air flow path, 5C ... Air discharge path, 10 ... Common separator, 11 ... Fuel center supply path , 11A ... tip opening, 12 ... air center supply path, 12A ... tip opening, 21 ... fuel supply manifold, 22 ... air supply manifold, 23 ... fuel exhaust manifold, 24 ... air exhaust manifold.

Claims (4)

A single cell of a flat plate solid oxide fuel cell (hereinafter referred to as flat plate SOFC) composed of a fuel electrode, an air electrode, and an electrolyte of a solid oxide, and a path for supplying fuel and air to the single cell A flat plate type SOFC stack formed by stacking power generation units each having a separator provided thereon and electrically connecting them in series,
The separator includes a fuel flow path plate provided with a fuel flow path for supplying the fuel to the fuel electrode, and an air flow path plate provided with an air flow path for supplying the air to the air electrode,
Separately from the separator, provided between the separators of the two power generation units adjacent to each other by the stacking, a fuel center supply path for supplying the fuel from a fuel supply manifold to one power generation unit, and an air supply manifold from the A common separator having an air center supply path for supplying air to the other power generation unit;
The fuel center supply path extends from the fuel supply manifold toward the center of the common separator in a groove shape on a first surface of the common separator that contacts the fuel flow path plate of the one power generation unit. And
The air center supply path is three-dimensionally connected to the fuel center supply path on a second surface of the common separator that is in contact with the air flow path plate of the other power generation unit and opposite to the first surface. Extending from the air supply manifold to the center of the common separator in a groove shape so as not to intersect
The fuel flow path plate is provided at a position facing a substantially central portion of the fuel electrode, and has a fuel supply hole that connects a front end opening of the fuel center supply path and a central portion of the fuel flow path. ,
The air flow path plate is provided at a position facing a substantially central portion of the air electrode, and has an air supply hole that connects a front end opening of the air center supply path and a central portion of the air flow path. A flat plate-type SOFC stack characterized by The flat plate-type SOFC stack according to claim 1,
The fuel supply hole is a circular hole having a radius including the center of the fuel electrode to the tip opening of the fuel center supply path,
The flat plate type SOFC stack, wherein the air supply hole is formed of a circular hole having a radius including the center of the air electrode and a tip opening of the air center supply path. The flat plate-type SOFC stack according to claim 1,
The fuel supply hole is composed of an elliptical or elliptical hole having a long diameter including from the center of the fuel electrode to the tip opening of the fuel center supply path,
The flat plate type SOFC stack, wherein the air supply hole is formed of an elliptical or elliptical hole having a long diameter including a center of the air electrode to a tip opening of the air center supply path. In the flat plate type SOFC stack according to any one of claims 1 to 3,
Either one or both of the fuel center supply path and the air center supply path has a slit shape penetrating the first surface and the second surface of the common separator, and is a flat plate type SOFC stack.

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